KR100465445B1 - Photo-induced Alignment Material for Liquid Crystal Alignment Film - Google Patents

Abstract

The present invention relates to an optical alignment material for a liquid crystal alignment film, and more particularly, to a liquid crystal alignment layer of a novel type in which a side chain structure containing no photoreactor is introduced into a maleimide-based homopolymer or copolymer to improve electrical characteristics. It relates to an optical alignment material.

Description

Photo-induced Alignment Material for Liquid Crystal Alignment Film

The present invention relates to an optical alignment material for a liquid crystal alignment film, and more particularly, to improve the reliability of a product by improving the electrical characteristics of the liquid crystal alignment film, which serves to control the liquid crystal by giving a uniform alignment state to the liquid crystal in the liquid crystal display device. A novel optical alignment material for liquid crystal alignment films for improvement.

The arrangement of the liquid crystals affected by the electric field is changed according to whether the external voltage is applied, and the liquid crystal display is driven using the property of blocking and transmitting external light flowing into the liquid crystal display. Such a liquid crystal display device has a function as a display device such as light transmittance, response speed, viewing angle, contrast ratio, etc. according to the arrangement characteristics of the liquid crystal molecules. Therefore, a technique of uniformly controlling the arrangement of liquid crystal molecules is very important.

The alignment film refers to a polymer material formed between a transparent conductive film such as indium tin oxide (ITO) and a liquid crystal for uniform alignment, that is, alignment of the liquid crystal molecules, and this may be a mechanical method such as rubbing. By other means it refers to a substance applied as a means for controlling the liquid crystal.

In the liquid crystal display device, a method of uniformly arranging or aligning liquid crystals to date has been performed by applying a polymer such as polyimide onto a transparent conductive glass to form a polymer alignment layer, while rotating a rotating roller wrapped with a rubbing cloth such as nylon or rayon at high speed. A method of rubbing an alignment film to align it is called a rubbing process. By the rubbing process, the liquid crystal molecules are aligned with a predetermined tilt angle on the surface of the alignment layer.

Since the liquid crystal alignment method by the rubbing process is almost the only way to align the liquid crystal easily and stably until now, most companies manufacturing liquid crystal display devices are generally applied to the process for mass production. However, the rubbing process causes mechanical scratches on the surface of the liquid crystal alignment film when rubbing, or generates high static electricity, which causes thin film transistors to break down and causes defects due to fine fibers generated in the rubbing cloth. It is an obstacle. The liquid crystal alignment method newly designed to overcome the problems of rubbing and to innovate the productive aspect is UV, that is, liquid crystal alignment by light (hereinafter referred to as photo alignment).

In addition, as the liquid crystal display has been enlarged in recent years, as the use of personal computers such as laptops is gradually expanded to home use such as wall-mounted TVs, high-definition, high-definition and wide viewing angles are required for the liquid crystal display. As a way to achieve the quality objectives of liquid crystal displays, optical alignment has recently been in the spotlight.

However, M. Schadt et al. (Jpn. J. Appl. Phys., Vol. 31, 1992, 2155), Dae S. Kang et al. (US Pat. No. 5,464,669), Yuriy Reznikov (Jpn. J. Appl. Phys., Vol. 34, 1995, L1000, et al., Despite the superiority of the concept, have yet to commercialize due to the difficulty in developing new materials to support them. The main reason for this is that it did not satisfy fairness enough to be applied to the existing liquid crystal display manufacturing process, or the display quality of the display did not reach a level comparable to the existing polyimide for rubbing.

On the other hand, the present inventors have proposed an optical alignment material having a structure in which a side chain structure including a cinnamate group is introduced into a homopolymer or copolymer of maleimide in Korean Patent Publication No. 2000-8633. However, there is still a lot of room for improvement since electrical and electro-optic properties are not sufficient to be applied to liquid crystal display devices.

The present invention is to solve the problems of the prior art as described above, and relates to a novel liquid crystal alignment film for the liquid crystal alignment film by introducing a side chain structure containing no photoreactor to improve the electrical properties of the alignment material.

That is, the present invention is a photoalignment material for a liquid crystal alignment film composed of at least one repeating unit selected from the group consisting of a repeating unit represented by the following Formula 1, or a repeating unit represented by the formula (1) and a repeating unit represented by the formula (2), wherein Equivalent ratio of the repeating unit comprising at least one photoreactor selected from the group consisting of functional groups represented by the following formula (5) among the repeating units constituting the photo-alignment material and the repeating unit consisting only of non-photoreactive groups is 2: It is characterized by being 8 to 10: 0, and more preferably relates to an optical alignment material for a liquid crystal alignment film, characterized in that 4: 4 to 9: 1.

[Formula 1]

[Formula 2]

Wherein X is a hydrogen atom, a linear or branched alkyl group having 1 to 14 carbon atoms, a fluorine atom, or a chlorine atom, Y is an oxygen atom or an alkylene group having 2 to 14 carbon atoms, and R is represented by the following Chemical Formula 3.

[Formula 3]

Wherein R ₁ is selected from the group consisting of functional groups represented by the following formula (4), R ₂ is selected from the group consisting of functional groups represented by the following formulas (5) and (6), R ₃ is composed of functional groups represented by the following formula (7) is selected from the group, k is an integer from 0 to 3, l is an integer from 0 to 5, wherein R _1, R _2, if a plurality of individuals each of R _1, R ₂ may be different from each other.

[Formula 4]

Wherein n is an integer from 0 to 10.

[Formula 5]

[Formula 6]

[Formula 7]

In the above formula, X is a hydrogen atom, an alkyl group or alkoxy group having 1 to 13 carbon atoms,-(OCH ₂ ) _p CH ₃ , a fluorine atom or a chlorine atom where p is an integer of 0 to 12, and m is an integer of 0 to 18.

Hereinafter, the present invention will be described in more detail.

The photo-alignment material of the present invention is composed of a maleimide-based homopolymer or copolymer. The maleimide-based polymer has excellent thermal stability compared to a conventional polyvinyl alcohol hydrocarbon polymer, and thus it is possible to secure thermal stability of 200 ° C. or higher, which is a process requirement temperature for manufacturing a liquid crystal display. Therefore, maleimide was introduced into the basic main chain structure to increase the thermal stability of the alignment layer.

In the present invention, in order to improve the electrical properties of the alignment layer, the repeating unit constituting the photo-alignment polymer is characterized in that the repeating unit having a photosensitive reactor and the repeating unit of the non-photosensitive structure are controlled at a constant ratio. That is, the repeating unit of the polymer is essentially included as the repeating unit constituting the polymer, thereby improving the electrical properties of the alignment layer.

In addition, by introducing functional groups such as fluorine and alkyl groups to reduce the electrical polarization phenomenon at the end of the side chain to further improve the electrical properties. Such materials are widely applied in the fields of optical materials and electronic materials because of their excellent transmittance, insulation, and electro-optical properties, and their scope of application is expanding day by day. However, such factors do not only give favorable properties to the material, but have many problems, particularly in film formation. Film formation is a concept that includes the coating and flatness of the material, the adhesion at the interface, etc. This is a very important process elements in the manufacturing of the liquid crystal display device. It is a general phenomenon that the higher the content of the elements, the lower the film formation property, but the present invention has been overcome by optimizing the content of these substituents and the substitution positions in the material.

In addition, when the alignment film having a high substitution rate of alkyl group and fluorine is used, the surface energy is very low, and the pretilt angle becomes higher than necessary, so that it cannot be used as a general TN mode liquid crystal display device. Introduced in position to minimize this phenomenon.

The photo-alignment material of the present invention having the above characteristics is at least one selected from the group consisting of a homopolymer consisting of a repeating unit represented by the following formula (1), or a repeating unit represented by the formula (1) and a repeating unit represented by the formula (2) It is a copolymer which consists of units.

Wherein X is a hydrogen atom, a linear or branched alkyl group having 1 to 14 carbon atoms, a fluorine atom, or a chlorine atom, Y is an oxygen atom or an alkylene group having 2 to 14 carbon atoms, and R is represented by the following Chemical Formula 3.

Wherein R ₁ is selected from the group consisting of functional groups represented by the following formula (4), R ₂ is selected from the group consisting of functional groups represented by the following formulas (5) and (6), R ₃ is composed of functional groups represented by the following formula (7) is selected from the group, k is an integer from 0 to 3, l is an integer from 0 to 5, wherein R _1, R _2, if a plurality of individuals each of R _1, R ₂ may be different from each other.

Wherein n is an integer from 0 to 10.

In the above formula, X is a hydrogen atom, an alkyl group or alkoxy group having 1 to 13 carbon atoms,-(OCH ₂ ) _p CH ₃ , a fluorine atom or a chlorine atom where p is an integer of 0 to 12, and m is an integer of 0 to 18.

The side chain structure constituting the optical alignment material of the present invention may be divided into a structure including a photoreactor represented by Formula 5 and a structure not including a photoreactor. As described above, the optical alignment material of the present invention is intended to obtain the effect of improving the electrical properties of the optical alignment material by adjusting the ratio of the structure including the photoreactor and the structure without the photoreactor. That is, the present invention has an equivalent ratio of a repeating unit including at least one photosensitive group selected from the group consisting of functional groups represented by Formula 5 and a repeating unit not including the same, that is, a non-photoreactive group is 2: 8 to 10: 0, and more. Preferably it is characterized in that it is adjusted to 4: 6 to 9: 1. The equivalence ratio of the repeating unit including the photoreceptor is 20% or more because it refers to the ratio of the minimum photoreactor for liquid crystal alignment. If the ratio is less than this, the alignment characteristic of the liquid crystal is significantly lowered, and thus it cannot act as an alignment material.

Formula 7 is a portion representing the end of the side chain structure to introduce a specific type of fluorine, chlorine, alkyl groups and the like to improve the electrical stability and optical properties as an alignment layer. At this time, at least one or more of X shown in the formula (7) is a fluorine atom improves the electro-optical properties. That is, by controlling the introduction form of these X and by controlling the degree of substitution and position, it was possible to synthesize a photo-alignment material showing more excellent electro-optic properties.

After dissolving the photo-alignment polymer having the above structure in a solvent and using it as an alignment layer instead of the existing rubbing polyimide, it is applied to the TFT substrate and the color filter substrate by printing method to form a photo-alignment film, and then the existing rubbing process Instead, a 3kW mercury lamp or the like may be used to proceed the exposure process for liquid crystal alignment with polarized ultraviolet rays. At this time, in the light energy that is used in conventional 200~2000J / cm ^2, and, in general, if the energy intensity is 50J / cm ² or higher degree it can orient the liquid crystal. At this time, a pretilt angle should be given to the liquid crystal in order to give a certain direction to the alignment of the liquid crystal. In order to realize this, inclination irradiation is performed by tilting the surface of the alignment film at a constant angle to the UV irradiation surface. This is the same principle as adjusting the pretilt angle by adjusting the intensity and frequency of rubbing by the method of orienting the liquid crystal in the existing rubbing process.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples are for the purpose of explanation and are not intended to limit the present invention.

1) Synthesis of Photo-alignment Material

Example 1

10 g (0.10 mol) of maleic anhydride and 10.1 g (0.09 mol) of aminophenol were added to 100 ml of toluene and stirred at room temperature for 2 hours to react in the form of amic acid, which was then reacted with acetic anhydride. ) And 100 ml of 4-acetoxyphenylmaleimide was prepared by dehydration reaction at 95 ° C. for 4 hours with 0.41 g (0.005 mol) of sodium acetate (CH 3 COONa). .

10 g (0.043 mol) of 4-acetoxyphenylmaleimide synthesized above was subjected to radical polymerization at 65 ° C. for 4 hours using 0.35 g of AIBN (2,2′-Azobisisobutyronitrile) as a polymerization initiator. Synthesized.

The polymer thus prepared was deprotected at 80 ° C. for 5 hours using 5 g of p-toluenesulfonic acid (p-TsOH) under 1 L of a mixed solvent of methanol / acetone to yield a polymer of the following formula in a yield of 85%. Synthesized.

Meanwhile, the side chain photoreactor was synthesized as follows. First, 10.2 g (0.075 mol) of 4-hydroxyacetophenone (4-hydroxyacetophenone) was dissolved in an aqueous NaOH solution (0.7% wv), and then 8 g (0.075 mol) of bezaldehyde was added and stirred at room temperature for 8 hours. The solution was neutralized with 5N HCl solution to synthesize 4-hydroxychalcone (50% yield) as follows.

11.2 g (0.05 mol) of 4-hydroxycalcon thus synthesized was dissolved in 60 ml of DMF (dimethyl formamide) and 60 ml of toluene, and then 8 g (0.06 mol) of K2CO3 was added and refluxed to remove water. 8.3 g (0.05 mol) of 4-fluorobenzoic acid was added thereto. Reflux for 24 hours to synthesize the desired product in 40% yield.

2.5 g (0.007 mol) of the side chain photoreactor thus synthesized was subjected to acyl chloride reaction under 20 ml of 1-methyl-2-pyrrolidinone, and triethylamine 1.09. After adding g (0.01 mol), the mixture was stirred for 1 hour at room temperature, and replaced with 1 g (0.003 mol) of the polymer synthesized above, thereby preparing the optical alignment material of the present example in a yield of 60%.

Example 2

Synthesis of the main chain structure of the polymer was in accordance with the synthesis process in Example 1. That is, 10 g (0.043 mol) of 4-acetoxyphenylmaleimide synthesized in the same manner as in Example 1, 6.97 g (0.043 mol) of acetoxystyrene, and 0.35 g of AIBN as a polymerization initiator were added to an acetone solvent. Radical polymerization at 4 ° C. for 4 hours synthesized a copolymer having the following structure.

Depolymerization of the polymer prepared above using 5 g of p-toluenesulfonic acid under a mixed solvent of methanol / acetone (1 L) at 80 ° C. for 5 hours to obtain the polymer main chain structure as described below. The polymer having was synthesized in a yield of 85%.

Meanwhile, in the case of the side chain reactor, it was synthesized as follows. First, 1 g (0.006 mol) of 4-carboxybenzaldehyde was reacted with 0.79 g (0.006 mol) of thionyl chloride (SOCl ₃ ) for 40 minutes in dichloromethane, followed by 50 ml of pyridine. 0.79 g (0.006 mol) of ethylmalonate was reacted at room temperature for 3 hours, and then subjected to an acyl-chloride reaction to synthesize an intermediate, ethyl-trans-chlorocarbonyl cinnamate, in a yield of 50%. The synthesized material was reacted with 0.98 g (0.006 mol) of 4-hydroxybenzoic acid and an aqueous NaOH / DMSO (dimethyl sulfoxide) solution at room temperature for 2 hours to give 60% of the side chain photoreactors as follows. It was synthesized in a yield of.

After 2.5 g (0.007 mol) of the synthesized side chain photoreactor was subjected to an acyl-chloride reaction, 1-methyl-2- with 1 g (0.003 mol) of the polymer main chain structure synthesized above and 1.09 g (0.01 mol) of triethylamine were synthesized. After dissolving in 20 ml of pyrrolidinone, the mixture was stirred at room temperature for 1 hour to prepare a photo-alignment material of this example in a yield of 60%.

Example 3

10 g (0.06 mol) of exo-3,6-epoxy-1,2,3,6-tetrahydrophtlic anhydride and 6.73 g of aminophenol (0.06 mol) was added to 100 ml of toluene, stirred at room temperature for 2 hours, and reacted in the form of amic acid. Then, this was dehydrated at 95 ° C with 2.46 g (0.03 mol) of sodium acetate in 100 ml of anhydrous acetate for 4 hours. Preparation of phenyl-3,6-epoxy-1,2,3,6-tetrahydrophthalicimide (4-Acetoxyphenyl-3,6-epoxy-1,2,3,6-tetrahydrophtalicimide) in 50% yield It was.

10 g (0.043 mol) of 4-acetoxymaleimide monomer synthesized in the same manner as in Example 1, 4-acetoxyphenyl-3,6-epoxy-1,2,3,6-tetrahydrophthalic 7.8 g (0.03 mol) of imide, 2.75 g (0.02 mol) of acetoxystyrene, and 0.71 g of AIBN as a polymerization initiator were added to an acetone solvent, followed by radical polymerization at 65 ° C. for 4 hours to form a three-way structure. The coalescence was synthesized.

The prepared copolymer was deprotected in the same manner as in Example 1 to synthesize a final polymer as follows in a yield of 85%.

5 g (0.013 mol) of this polymer was dissolved in 50 ml of 1-methyl-2-pyrrolidinone, followed by 4.7 g (0.468 mol) of triethylamine and 6.1 g of 4-methoxycinnamoylchloride as a side chain reactor. (0.03 mol) was added and substituted by a method of stirring at room temperature for 1 hour to prepare a photo-alignment material of this example in a yield of 60%.

Example 4

10 g (0.043 mol) of 4-acetoxyphenylmaleimide synthesized in the same manner as in Example 1, 4.2 g (0.025 mol) of acetoxy styrene, 1.43 g (0.016 mol) of vinyl acetate and 0.35 g of AIBN as a polymerization initiator in an acetone solvent Into the radical polymerization at 65 ℃ for 4 hours to synthesize a terpolymer as shown in the following formula.

The prepared polymer was deprotected at 80 ° C. for 5 hours using 5 g of p-toluene sulfonic acid under 1 L of a mixed solvent of methanol / acetone to synthesize a polymer of the following formula in a yield of 85%.

After adding 2.54 g (0.025 mol) of triethylamine in 50 ml of 1-methyl-2-pyrrolidinone in the same manner as in Example 1 to 1 g (0.007 mol) of the polymer synthesized as described above, the mixture was stirred at room temperature for 1 hour. By replacing 5.8g (0.017mol) of the photoreactor prepared in Example 2 to prepare a photo-alignment material of this Example in a yield of 60%.

Example 5

Synthesis of the main chain structure of the polymer was in accordance with the synthesis process in Example 1.

In the side chain reactor, 1 g (0.006 mol) of cinnamic acid was reacted with 0.71 g (0.006 mol) of thionyl chloride under methane dichloride for 1 hour at 35 ° C. to synthesize cinnamoyl chloride, followed by 0.98 g of 4-hydroxybenzoic acid. (0.006 mol) was reacted at room temperature for 1 hour using an aqueous NaOH / DMSO solution.

The synthesized product was reacted with thionyl chloride by acyl-chloride reaction with 1.5 g (0.005 mol) of side chain photoreactor and 0.24 g (0.002 mol) of valeryl chloride. mol) to synthesize a photo-alignment material of the following structure in a yield of 60%.

Example 6

10 g (0.043 mol) of 4-acetoxyphenylmaleimide synthesized in the same manner as in Example 1, 2.31 g (0.018 mol) of n-butyl acrylate (n-Butylacrylate), and 0.35 g of AIBN as a polymerization initiator in an acetone solvent The mixture was charged and subjected to radical polymerization at 65 ° C. for 4 hours to synthesize a copolymer as described below, followed by deprotection at 80 ° C. for 5 hours using 5 g of p-toluene sulfonic acid under 1 L of a mixed solvent of methanol / acetone. Copolymers were synthesized in 85% yield.

1 g (0.006 mol) of the polymer main chain structure synthesized as described above was dissolved in 50 ml of 1-methyl-2-pyrrolidinone, followed by 4.0 g (0.014 mol) of the side chain reactor synthesized in Example 5 and 2.36 g (0.023 mol) of triethylamine. ) Was added and then stirred at room temperature for 1 hour to prepare a photo-alignment material of this example in a yield of 50%.

Example 7

Synthesis of the main chain structure of the polymer was in accordance with the synthesis process in Example 1.

Meanwhile. The side chains were synthesized as follows. 50 g (0.3 mol) of 4-hydroxycyinnamic acid was dissolved in an aqueous NaOH solution (0.25 wv%), followed by DMSO, followed by 2,6-difluorobenzoyl chloride. g (0.3 mol) was added. After stirring for 1 hour at room temperature, the desired product was synthesized by neutralization with 4N HCl solution.

2,6-difluorobenzoxy-4.4'-cinamoyl chloride (2,6-Difluorobenzoxy-4,4'-Cinnamoyl Chloride) synthesized as described above with 0.7 equivalents (17 g, 0.055 mol) and 3,4-di Poly (4-hydroxyphenylmaleimide-alt-4-hydroxystyrene) (0.3 (3,4-Difluorocinnamoyl Chloride) 0.3 equivalent (7.3 g, 0.02 mol)) as the main chain of poly (4-Hydroxyphenylmaleimide -alt-4-Hydroxystyrene)) 0.91 g (0.009 mol) of triethylamine was added to 10.2 g (0.032 mol) under 20 ml of 1-methyl-2-pyrrolidinone, followed by stirring at room temperature for 1 hour for substitution. Photo-alignment material was synthesized in a yield of 60%.

2) Fabrication and Characterization of Liquid Crystal Display Devices

The photo-alignment material obtained above was dissolved in a mixed solvent of 1-methyl-2-pyrrolidinone and 2-butoxyethanol, and applied to the TFT substrate and the color filter substrate by printing to form a photo alignment layer. After the film formation, an exposure process for liquid crystal alignment was performed with polarized ultraviolet rays using a 3 kW mercury lamp. All other processes except the exposure process produced a 15 "liquid crystal display in accordance with the general liquid crystal display (LCD) manufacturing process. The liquid crystal display device thus manufactured was used as a display to display the basic electro-optical characteristics such as black and white contrast ratio, The response speed, viewing angle, luminance, etc. were evaluated and summarized in Table 3. In the same manner, a small 1 "unit cell was fabricated, and the voltage retention and residual DC, which are electrical characteristics of the alignment layer, were measured. Summarized. The liquid crystal used Merck liquid crystal used for TN mode TFT-LCD.

Comparative Example 1

Using a polyimide (SE 7992, Nissan Chemical), which is widely used as an alignment agent for rubbing, a liquid crystal display and a cell were produced in the same manner as above to measure physical properties.

Comparative Example 2

The physical properties of the liquid crystal display and the cell were prepared by the same method as described above using the optical alignment material of the following structure disclosed in Korean Patent Laid-Open Publication No. 2000-8633.

Table 1 shows the voltage holding ratio measured in Examples 1 to 6 and Comparative Examples 1 and 2, and Table 2 shows the residual DC value, showing better voltage holding ratio and residual DC characteristics than Comparative Example 1. It can be seen that the problem of the conventional optical alignment material is improved a lot. Voltage holding ratio and residual DC value are very important in terms of reliability and electrical stability of display quality. Especially, it is recognized as a cause factor of afterimage phenomenon, which is the weakest characteristic of liquid crystal display device along with response speed in natural implementation of video. It is becoming. The voltage retention showed the characteristic superior to the comparative example 1 using the existing aligning agent for rubbing, and especially the characteristic improved compared to the aligning agent for rubbing in residual DC value.

Voltage retention rate Measuring temperature Room temperature (25 ℃) 60 ℃ Comparative Example 1 99.1% 95.2% Comparative Example 2 97.5% 92.4% Example 1 97.9% 95.5% Example 2 98.3% 94.5% Example 3 98.8% 95.1% Example 4 99.5% 97.7% Example 5 99.1% 96.1% Example 6 99.2% 97.3% Example 7 99.8% 98.4%

※ Measurement condition: voltage 1V, voltage holding time 64㎲, frequency 60Hz

Residual DC Max. △ C Comparative Example 1 31.2 × 10 ^-9 F Comparative Example 2 55.2 × 10 ^-9 F Example 1 21.7 × 10 ^-9 F Example 2 17.0 × 10 ^-9 F Example 3 8.9 × 10 ^-9 F Example 4 5.4 × 10 ^-9 F Example 5 6.2 × 10 ^-9 F Example 6 5.6 × 10 ^-9 F Example 7 4.3 × 10 ^-9 F

※ Method of measurement: Measure the capacitance repeatedly by applying voltage from (-20V) to (+ 20V) on the unit cell, and compare the point that the difference of capacitance (△ C) is the maximum at the same voltage. calculation.

Electro-optical Characteristics in 15 "TFT LCD Black and White Contrast Ratio Response speed (msec) Luminance (cd / m ² ) Viewing angle Right and left Up / down Comparative Example 1 200 35 200 58/58 45 /> 60 Comparative Example 2 185 32 205 58/59 45 /> 60 Example 1 247 32 195 58/58 45 /> 60 Example 2 205 29 201 59/58 45 /> 60 Example 3 212 25 207 58/58 45 /> 60 Example 4 225 27 205 59/58 45 /> 60 Example 5 224 29 211 58/58 45 /> 60 Example 6 218 26 208 59/58 45 /> 60 Example 7 237 26 210 58/59 45 /> 60

※ The black and white contrast ratio and luminance are the average values measured at nine positions to the center and periphery of the screen.

According to the present invention, it was possible to improve the electrical characteristic value required for improvement in the optical alignment material over polyimide, which is a rubbing alignment agent. The optical alignment material for liquid crystal aligning film which can exhibit a level can be provided.

Claims (5)

A photoalignment material for a liquid crystal alignment film comprising one or more repeating units selected from the group consisting of a repeating unit represented by Formula 1, or a repeating unit represented by Formula 1 and a repeating unit represented by Formula 2, wherein the photoalignment material Equivalent ratio of the repeating unit comprising at least one photoreactor selected from the group consisting of functional groups represented by the following formula (5) and the repeating unit consisting only of the non-photoreactive group of 2: 8 to 10: The optical alignment material for liquid crystal aligning film characterized by being 0. [Formula 1] [Formula 2] Wherein X is a hydrogen atom, a linear or branched alkyl group having 1 to 14 carbon atoms, a fluorine atom, or a chlorine atom, Y is an oxygen atom or an alkylene group having 2 to 14 carbon atoms, and R is represented by the following Chemical Formula 3. [Formula 3] Wherein R ₁ is selected from the group consisting of functional groups represented by the following formula (4), R ₂ is selected from the group consisting of functional groups represented by the following formulas (5) and (6), R ₃ is composed of functional groups represented by the following formula (7) is selected from the group, k is an integer from 0 to 3, l is an integer from 0 to 5, wherein R _1, R _2, if a plurality of individuals each of R _1, R ₂ may be different from each other. [Formula 4] Wherein n is an integer from 0 to 10. [Formula 5] [Formula 6] [Formula 7] In the above formula, X is a hydrogen atom, an alkyl group or alkoxy group having 1 to 13 carbon atoms,-(OCH ₂ ) _p CH ₃ , a fluorine atom or a chlorine atom where p is an integer of 0 to 12, and m is an integer of 0 to 18. The repeating unit of claim 1, wherein the repeating unit comprising at least one photoreactor selected from the group consisting of functional groups represented by Formula 5 among the repeating units constituting the optical alignment material does not include the repeating unit, that is, only non-photoreactive groups. The liquid crystal alignment film optical alignment material, characterized in that the equivalent ratio of 4: 6 to 9: 1. The optical alignment material for liquid crystal alignment film according to claim 1, wherein at least one fluorine group is substituted with -R ₃ representing the end of the side chain structure introduced into the optical alignment material. The optical alignment material of claim 1, wherein the optical alignment material comprises a styrene series repeating unit among the maleimide series repeating unit represented by Formula 1 and the repeating unit represented by Formula 2. The optical alignment material of claim 1, wherein the optical alignment material comprises a cinnamate group among functional groups represented by Chemical Formula 5 as a photoreactor.